Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 45 to 54.
A. signal
B. a sign
C. a gesture
D. a symbol
* Đáp án
* Hướng dẫn giải
Đáp án : D
Dòng 2 đoạn 2: applauding in a theater provides performers with an auditory symbol of approval